Fixed up one off connection clients for Sequelize (if client is already defined …

…simply callback rather than connecting again).

lib/dialects/postgres/connector-manager.js

@@ -121,10 +121,14 @@ module.exports = (function() {
       this.poolIdentifier = this.pg.pools.getOrCreate(this.sequelize.config)
       this.poolIdentifier.connect(connectCallback)
     } else {
+      if (!!this.client) {
+        connectCallback(null, this.client);
+      } else {
         //create one-off client
         this.client = new this.pg.Client(uri)
         this.client.connect(connectCallback)
       }
+    }
 
     return emitter
   }